We Googled this and did not find the exact answer we were looking for. Can we insert an image as a background in Drawings? We can insert the image and order the image to the back but we wanted it as a background instead.
In Slides, the answer would be YES! So why is this feature not available in Drawings?? You can insert an image and send it to the back just like you said, but it's still just like a poster on the wall; it can be moved around, unlike wallpaper. PLEASE, I beg of you, send that as feedback to Google!!
This very important feature is hidden inside the Help menu in Drawings, and disguised as "Report a problem" instead of feedback. When you click on it, you will see the FEEDBACK window pop up - like this: